1. Field of the Invention:
This invention relates to apparatuses for winding magnetic tape into cassette cases with guard panels, and especially relates to apparatuses which extract leader tape from a cassette case, connect magnetic tape between the leader tape, and wind the tape onto a hub inside the cassette case.
2. DESCRIPTION OF THE RELATED ART:
The trend in magnetic tape in recent years has been toward higher recording density, and as a result, the sensitivity to foreign particles on the tape surface has increased. Foreign objects on the surface of magnetic data tape, used in computers, etc., are a cause of data recording errors. Foreign objects on the surface of video tape are a source of interference and poor picture quality. Foreign objects on the surface of audio magnetic tape, recorded by PCM, etc., are a source of noise.
There are two basic production methods for magnetic recording tape cassettes. The first method involves loading cassette cases with reel hubs which have already been wound with magnetic tape outside the case. This method requires a large complex apparatus, but the magnetic tape winding time is short, and the processing rate is high. This method is suitable for large scale production facilities.
In the second method, cassettes are prepared by loading reel hubs joined by a length of leader tape into cassette cases. Leader tape is extracted from each cassette case, magnetic tape is connected to the leader tape, and a hub is rotated to wind magnetic tape into the cassette case. This method can be performed by a simple apparatus, and since the magnetic tape goes directly into the cassette case upon winding, the amount of dust and foreign object attachment to the tape surface can be reduced.
The present invention is an improved apparatus performing the second method, which was specially developed to reduce the amount of dust attachment to the surface of the magnetic tape.
An apparatus, which extracts leader tape from a cassette case, connects magnetic tape, and winds the magnetic tape into the case, is known (Japanese Patent Publication No. 45203/1977). In this apparatus, as shown in FIG. 9, leader tape 92 is extracted from the cassette case 91, is and attached to the first 93 and second 94 tape retainers. The leader tape 92 is cut between the first 93 and second 94 tape retainers to which it is attached, and the third tape retainer 95, which moves as a unit with the second tape retainer 94 and holds magnetic tape 96, is moved next to the first tape retainer 93. Magnetic tape 96 is connected to the end of the leader tape 92, the tape is released from the first 93 and third 95 tape retainers, and the hub inside the cassette case is rotated to wind up the tape. After a predetermined length of magnetic tape 96 has been wound, it is again attached to, and cut between, the first 93 and third 95 tape retainers. The second 94 and third 95 tape retainers are then moved such that the second tape retainer 94 is put next to the first tape retainer 93, the end of the magnetic tape 96 is joined to the previously cut end of the leader tape 92, and the remaining extracted tape is wound into the cassette case.
In addition to this, an apparatus with a different system of supplying magnetic tape to the severed leader tape has also been developed (Japanese Patent Publication No. 30444/1974). In this apparatus as well, leader tape is extracted from the cassette case, the leader tape is cut, and magnetic tape is joined to one end of the leader tape. After magnetic tape is wound into the cassette case, it is cut, and joined to the other end of the leader tape.
These former models have the drawback that since the tape cutting and splicing mechanisms are relatively far from the cassette case, a considerable length of leader tape is extracted from the cassette, and thus, dust and other foreign particles easily collect on the leader and magnetic tape surfaces during cutting and splicing.
The recording and playback quality of high quality magnetic tape depends critically upon the minimization of dust and other foreign particles on the tape surface. In particular, particles such as dust attach to the polyester of other synthetic resin type leader tape which is extracted from the cassette case. Since synthetic resin film like polyester film is a good insulator and its surface is easily charged, static electricity attracts foreign particles. Since magnetic materials like iron oxide and pure iron are attached to the surface of magnetic tape, it is more conductive than leader tape, and consequently less likely to become statically charged and pick up dust, etc. than leader tape. There is no degradation of recording or playback quality as long as dust and foreign objects attached to the surface of the leader tape are not transferred to the magnetic tape. However, the foreign objects attached to the leader tape get on the surface of cassette parts such as the guide rollers, and are transferred to the magnetic tape. Therefore, it is important to minimize leader tape dust and foreign object attachment for high density magnetic recording applications.
Once tape has been wound into the cassette case, almost no dust gets on the tape inside, but the tape between the reels exposed outside the cassette is easily contaminated. Therefore, cassette cases equipped with guard panels, that are free to open and close over the exposed tape, preventing dust, and contamination during nonuse, etc., are employed.